Treatment of cashew nut shell



Patented bet. 17, 1939 Solomon Caplan, New York, N. Y., assignor to The Harvel Corporation, a corporation of New Jersey No Drawing.

Application November 6, 1936, Serial No. 109,470

16 Claims. (01. 260-46) The present invention relates generally to methods and steps for the polymerization of phenols having unsaturated side chain substituents on the phenol nucleus whether synthetic or of natural sources such as materials of this kind obtained or derived from the Anacardium genus of the Anacardiaceae family and including cashew nut shell liquid, marking nut shell liquid, Japanese lac and unsaturated side chain phenolic products obtained or derived from these materials such as anacardic acid, Cardanol, Cardol,

urushiol, and the phenolic constituents of mark-' ing nut shell liquid; and the present invention relates more particularly to methods and steps for the polymerization of the above identified materials and products by the use of monoalkyl I acid sulphates and dialkyl sulphates, withthe aid of heat.

The present invention is a departure from the invention described in Patent Number 1,725,793

of M. T. Harvey who uses strong acids such as sulphuric acid, among other material, for the treatment of cashew nut shell liquid; and it is an object of the present invention to obtain a 25. slower polymerizing reaction than is given by strong acids, for the purposes of facilitating the handling of the material being polymerized, as examples, to allow time to pour large batches from mixing kettles into curing pans, also to get 30 ,the sulphate thoroughly and uniformly dispersed throughout the material to be treated before reaction is initiated, and without the use of solvents which do not enter into the reaction and which eventually have to be removed.

35 The present invention is especially advantageous in making polymerized products for electrical insulation in that it eliminates the possi- ,bility of the occlusion of water or unpolymerized material in the polymerized product, such as may 40 occur when water is used to dilute sulphuric acid "employed for polymerizing to 'thesolid state.

' Also, monoalkyl acid sulphates, dialkyl sulphates, and sulphuric acid can be used at different steps of the polymerization. For example,

quantity as to produce a polymerized product which is liquid, after which a monoor di-alkyl 1 sulphate is mixed in and used to bring the treatsulphuric acid can be used for a preliminary polymerization and used in such predetermined cles from cashew nut shell quid, as hereinafter more fully set forth.

Also, mixtures can be used of any two or of the three sulphate radicle bearing materials,

namely, sulphuric acid, alkyl acid sulphate (monoalkyl acid sulphate) and dialkyl sulphate. In the case of a'mixture of sulphuric acid with either or both the monoalkyl acid'sulphate and the dialkyl sulphate, the sulphuric acid dissolves in the alkyl sulphate and the advantage of using 10 a solvent for the sulphuric acid is obtained together with the advantage gained from the use of an alkyl sulphate.

Other objects and advantages ofthe present invention will be apparent from the foregoing disclosure of illustrative examples of methods, steps, uses and products of the present invention.

The following are given as examples of phenols which have unsaturated side chains and-whose polymerization can be promoted by material se- 0 lected from the group consisting of dialkyl sulphates and monoalkyl acid sulphates: the so defined phenols obtained from or derived from juices of the Anacardium genus of the Anacardiaceae family including cashew nut shell liquid and itsphenolicderivatives such as Cardol, anacardic acid; Cardanol which is a breakdown derivative of anacardic acid, and other phenolic derivatives of the kind defined obtained some in -the.distillate and some in the residue left after distillation, marking nut shell liquid and its phenolic constituents anacardol and the carboxylic phenols, its phenol distlllates and phenol distillate residues having unsaturated side chains; Japan lac and its phenolconstituents and derivatives including urushiol,, distillates and distillate residues; and in'general those phenols which have unsaturated side chains and which can be polymerized by concentrated or fuming sulphuric acidr 40 As examples of dlalkyl and monoalkyl acid sulphates suitable for the practice of the methods of the present invention the following are given: dimethyl sulphate, diethyl sulphate, dibutylsulphate, dipropyl sulphate, diamyl sulphate and the -mixed-alkyl sulphates such as ethyl butyl sulphate, butyl amyl sulphate, mono-ethyl acid sulphate, monopropyl acid sulphate, mono-iso-- propyl acid sulphate and so on.

' Illustrative examples of method of polymer.- izing cashew nut shell liquid and other materials according to the present invention are as follows:

EXAMPLE I.(Step 1) .To' two tons (4000 pounds) of cashew nut shell liquid in a steel tank about one hundred twenty pounds (3% by weight I or the cashew nut shell liquid) a commercial grade of mono-isopropyl acid sulphate are added and thoroughly mixed with an agitator and the mixture heated by means of steam passed through coils of pipe immersed in the mixture, the agitation being continued during the heating. The heating is carried on until the temperature of the mixture reaches 325 F. which takes about one and one-half hours to two hours in the particularapparatus used for the present example. 0n reaching the desired temperature the steam is turned off to discontinue the heating. During this heating the mono-isopropyl acid sulphate reacts with metal bearing compounds in the cashew nut shell liquid whereby the metals are precipitated as the sulphate salts. Also, the cashew nut shell liquid is thickened due to the polymerizing action of the mono-isopropyl acid sulphate. On reaching the desired temperature the treated cashew nut shell liquid is drawn from the tank and pumped while still hot through a filter press to remove the precipitated salts, which latter, upon their precipitation remain for some time in suspension in the cashew nut shell liquid, serve as a filter aid in the press and build up a cake through which the cashew nut shell liquid passes. This treated and filtered cashew nut shell liquid, hereinafter called treated cashew nut shell liquid, upon cooling is liquid and of slightly higher viscosity than commercial untreated cashew nut shell liquid and is stored in tanks for use and is suitable for making varnishes, resins as by reaction with aldehydes, and for other uses for which cashew nut shell liquid is known to be suitable, including further polymerization to various stages including among others the liquid, semi-liquid and rubbery states in which latter state the product is known by the trade-mark name of "Cardolite.

Step 2.--About ten pounds each of water and concentrated sulphuric acid are mixed with an agitator into one thousand pounds of the above treated cashew nut shell liquid" in a jacketed copper lined kettle and heated by steam to a temperature of about 320 F. where considerable 'frothing occurs, at which point the steam is turned on and cold water circulated through the Jacket to retard further polymerizing reaction.

The resulting product can be drawn oil for storage or immediate use as soon as the above temperature is used. The product when cooled to normal temperature is a thick liquid and is suitable i'or the various uses of cashewnut shell liquid including those above noted for "treated cashew nut shell liquid".

Step 3.-A further step for treatment according to the present invention is to let the material of Step 2 remain .in the kettle and hold until the temperature rises 285 E, which rise will occur with the steam 0E and cold water flowing through the jacket, at which point about twenty pounds of commercial diethyl sulphate are added and mixed until the temperature reaches 250 F. when the material is drawn from the kettle and into shallow pans for a depth of about three inches. To get a rubber like consistency, the material called "Cardolite", the material in the shallow pans is placed in ovens and cured for about fifteen hours at about 260 F. to 275 F.

Exnnmn II.To agiven quantity of the treated cashew nut shell liquid" of Step 1 of Example I there is added about two per cent by weight of diethyl sulphate which is stirred in to 'get a uniform solution of the two. The solution is then heated to bring it up to about 320 F. whereupon the heating is discontinued and the material held until frothing' caused by evolution of sulphur dioxide gas subsides, whereupon the material is poured into shallow pans andset in oven to cure for about fifteen hours at about 260 F. to 275 F. The resulting product is a resilient solid, rubberlike in character, and, like the corresponding material in Step 3 of Example I above, is known on the market as Cardolite.

Exauru: IIL-The phenolic material of this example is the residue remaining after the distillation of cashew nut shell liquid with steam at about 270 F., and is hereafter in this example called residue. "Residue" is comprised mostly of phenols having an unsaturated side chain and having a high molecular weight. Into one hundred parts of residue were dissolved five parts by weight of diethyl sulphate and the solution heated to about 160 C. where polymerization produced a strong resinous material resistant to high temperature and an insulation of high voltage and frequency currents.

Emma: IV.To one hundred parts by weight of Japanese lac (vernisifera) were added five parts by weight of diethyl sulphate which was stirred in and the solution heated up to about 120 C. until the Japanese lac was polymerized to a ropy consistency when it was set in an ovn at about 160 C. for about three hours when it became polymerized and set to a tough, hard resin.

Metal salts are precipitated: from Japanese lac by the sulphate radicles and the precipitate can be removed as by filtering before polymerization of the Japanese lac goes beyond the liquid or filterable state.

Having thus described my invention, what I claim and desire to protect by Letters Patent is:

1. In a method of polymerizing cashew nut shell liquid the step which comprises dissolving therein material selected from the group consisting of mono alkyl acid sulphates and dialkyl sulphates, and heating.

2. In a method of polymerizing cashew nut shell liquid the step which comprises heating a solution of material selected from the group consisting of mono alkyl acid sulphates and dialkyl sulphates in cashew nut shell liquid.

3. The method which comprises dissolving sulphuric acid in a dialkyl sulphate, dissolving the above solution in cashew nut shell liquid, and heating to produce polymerization of the cashew nut shell liquid.

4. The method which comprises dissolving a dialkyl sulphate in cashew nut shell liquid and heating to produce polymerization of the cashew nut shell liquid.

5. In the treatment of cashewnut shell liquid the step which comprises intimately mixing therein material selected from the group consisting of dialkyl sulphates and monoalkyl acid sulphates, heating to precipitate salts of metals occurring in cashew nut shell liquid, and removing the precipitated salts.

6. The method of polymerizing a phenol having an olefinic hydrocarbon side chain on the benzene nucleus thereof which comprises heating therewith material selected from the group consisting of dialkyl sulphates and monoalb'l acid sulphates.

7. The method of polymerizing cashew' nut shell liquid which comprises heating therewith sulphuric acid dissolved in material selected from the group consisting of dialkyl sulphates and monoalkyl acid sulphates.

8. The method oi polymerizing a phenol having an oleflnic hydrocarbon side chain on the benzene nucleus thereof, derived from a member of the Anacardium genus of the Anacardiaceae family, which comprises heating said defined phenol in intimate contact with material selected from the group consisting of dialkyl sulphates and monoalkyl acid sulphates.

9. The method which comprises dissolving sulphuric acid in cashew nut shell liquid with the aid of a dialkyl sulphate and heating the cashew nut shell liquid in contact with said solution to produce polymerization of the cashew nut shell liquid.

10. In the polymerization of cashew nut shell liquid the step comprising dissolving a dialkyi sulphate in partially polymerized cashew nut shell liqgid and heating to produce further polymerim on.

11. Themethod comprising promoting the polymerization of cashew nut shell liquid by heating in contact with an dbl ester of sul- Dhuric acid.

12. The method which comprises dissolving in cashew nut shell liquid a solution of sulphuric als, andremoving the precipitate.

13. The method which comprises dissolving material selected from the group consisting of monoalkyl acid sulphates and diaikyl sulphates in a phenolic compound having an unsaturated open chain hydrocarbon substituent on the nucleus and having at least one of the readily reactive positions unsubstituted, and heating to promote polymerization.

' 14. The method which comprises dissolving a dialkyl sulphate in cashew nut shell liquid, heating to promote polymerization to a predetermined degree, and cooling to retard iurther polymerization.

15. The method of promoting the polymerization of a phenol product 01' a member of the Anacardium genus oi the Anacardiaceae family, which phenol has an unsaturated hydrocarbon side chain, which comprises heating with material selected from the group consisting of dialkyl sulphate and mono alkyl acid sulphates.

16. The method which comprises dissolving material selected from the group consisting of dialkyl sulphates and monoaikyl acid sulphates in the juice or a member of the Anacardium genus of the Anacardiaceae family, heating .to react the material selectedwith metals naturally occurring in said Juice and thereby to precipitate the salts of said metals and removing the precipltate.

sonbuou cm. 

